Re: How to do numerical computations?
- To: mathgroup at smc.vnet.net
- Subject: [mg108813] Re: How to do numerical computations?
- From: dr DanW <dmaxwarren at gmail.com>
- Date: Thu, 1 Apr 2010 06:01:58 -0500 (EST)
- References: <hov834$94q$1@smc.vnet.net>
I'm taking a guess that you have a fairly complicated Block[] or
Module[] with an integration that involves some parameters.
Mathematica is hitting that integration and trying to evaluate it
symbolically, which can be time consuming. I think what you want to
do is prevent that integration from evaluating until it gets numerical
values for the parameters. One way to do this is to create a function
out of the integration that requires numerical input. A trivial
example is
int[a_?NumericQ] := NIntegrate[ Sin[x] , {x, 0, a} ]
This way, when you say
b = int[c]
where c has no value, Mathematica will hold it as int[c] and not
attempt a symbolic evaluation. Later, you can say c = 3., and the
numerical integration can be evaluated quite quickly.
Daniel